The electrically-operated machine is generally provided with an emergency switch serving as a safety device. The emergency switch is activated under circumstances demanding an immediate cessation of operation of the machine.
As shown in FIGS. 1-3, the Taiwan Patent Serial Number 90207473 discloses an emergency switch 1 comprising a cover 2 which is formed of a frame 3 and a press piece 4 fastened to the frame 3. In the event that the emergency switch 1 has to be activated, the press piece 4 is pressed with finger to separate from the frame 3, thereby making the emergency switch 1 accessible. The press piece 4 is intended to prevent the emergency switch 1 from being activated accidentally.
Such a prior art emergency switch as described above is defective in design in that the activation of the emergency switch is delayed by a chore of severing the press piece, and that the finger of a machine operation is susceptible to injuries in the course of severing the press piece, and further that the emergency switch must be provided with a new cover in the wake of the activation of the emergency switch.
As shown in FIGS. 4 and 5, a prior art emergency switch 5 is mounted on a control panel 6 such that the emergency switch 5 is immediately accessible. This prior art emergency switch is vulnerable to an accidental activation. In addition, it is devoid of a means to enable a machine operator to tell with ease and speed if the emergency switch is in the state of activation or inactivation.